During the summer and fall of 1998, I began a search for improved varieties of bur oak, Quercus macrocarpa. I examined a few thousand two year old nursery grown trees of Quercus macrocarpa growing in rows at a nursery in Boring, Oreg. These trees had been planted from seed. At various times during the summer and fall, I tagged the most promising looking trees in these nursery rows. I was selecting for disease resistance, straightness, growth rate, foliage appearance, fall color, and defoliation. By the time the trees had gone dormant, I had selected what I believed to be the 21 most promising individual trees in the block.
In the spring of 1999, I transplanted these trees into testing rows in the nursery. I labeled each tree, and over the next two summers I evaluated the appearance and performance of these trees and recorded notes. After two years of evaluation, I selected the best seven trees and transplanted them in 2001 into a long term evaluation block with wider spacing. I rejected and destroyed the remaining 14 trees as being of lesser quality.
Over the next several years, I examined my seven selected bur oak trees, photographed them, and took detailed notes regarding their features. In this evaluation, my new variety ‘JFS-KW3’ emerged as the best selection in terms of the superior characteristics that I was seeking. The parent trees to ‘JFS-KW3’ were unnamed, unpatented trees of the species Quercus macrocarpa. In 2003, 2005, 2006, 2007, and 2008, I propagated small plots test plots of my new variety at the nursery in Boring, Oreg., by chip budding onto seedling Quercus macrocarpa rootstock. From this propagation, I established that the characteristics of a straight upright trunk, a narrowly oval to narrowly pyramidal upright growth habit, dark green foliage and resistance to powdery mildew (Erysiphe alphitoides) and anthracnose (Apiognomonia quercina) of my new variety are unique and firmly fixed in each successive generation.
In the fall of 2006, the original tree of my new variety began producing acorns. These acorns were unusual in that they were extremely small acorns for the species, a desirable characteristic for landscape use. The acorns have yet to be observed in the asexually propagated progeny because the progeny are too young to have acorns, but the acorn characteristic is expected in this progeny.